As a bug drops vertically from a point meters above a bush to a leaf on the bush, its gravitational potential energy Ug(y) 1. remains constant. 2. increases by the amount of work you would have to do against gravity to carry the bug from the leaf to its original position. 3. increases by the amount of work gravity does on the bug as it drops. 4. decreases by the magnitude of the amount of work gravity does on the bug as it drops.

4. decreases by the magnitude of the amount of work gravity does on the bug as it drops

Explanation:

Potential energy increases the higher it gets from it's starting point. For this question the starting point would be the bush and the bug is a certain point above it so it has a lot of potential energy. The gravitational potential energy decreases as it drops and gets closer to the leaf on the bush.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia